Natural menopause is described as the physiological period which occurs after twelve months past the last women's menstruation cicle, iniciating in general over 45 years old. On the other hand, cirurgical menopause has premature commencement, succeding the ovarian removal surgery – bilateral oopherectomy – wich could also be accompained by the uterus removal surgery -  hysterectomy. The menopausal symptoms are similar between its aetiologies as well as the hormonal defficts has various consequences to the pelvic floor muscles (PFM) as its hypotrophy and muscle fiber substitution by adipocytes. Therefore, there is a strong correlation between the changes in PFM and urinary incontinence (UI) cases. However, due to its premature commencement, health conditions wich led to the surgery as well as the fact of the ovaries keep producing low rates of estrogen in natural menopause, cirurgical menopause may impacts womens health severely in comparision to natural menopause. Thus, this study aims to compare pelvic floor muscle pressure in post-menopaused women who had cirurgical menopause and natural menopause.

A cross-sectional study of 117 volunteers allocated by spontaneous demand and divided into two groups: natural menopause (NM; n = 62) and surgical menopause (SM; n = 55). The study included women over 18 years of age who did not have the hymen intact, without urinary or vaginal infection and without gynecological bleeding. An evaluation form was used to collect sociodemographic and clinical informations. The manometer used was Peritron® model 9300V. For the manometric evaluation, the volunteer remained in a gynecological position, being naked from the abdomen downwards. Guidance was given on the correct form of contraction of PFM, dissociating from the abdominal muscles, adductors of the hip and gluteal muscles. The volunteer was also instructed to breathe normally, avoiding the valsalva maneuver and to perform the muscular contraction with the greatest strength she could. The vaginal probe was covered with an unlubricated latex condom and inserted into the vaginal cavity. Three maximum voluntary contractions (MVCs) were performed with a 30 second interval between them, and was given the command of "tighten the probe". The information collected was tabulated in the IMB program Statistical Package for the Social Sciences (version 20.0) for Windows. The descriptive statistics were used to present the clinical data and for comparison between the type of menopause and PFM  manometry, the T test was used for independent samples. This study was approved by the research ethics committee

It were analyzed 109 volunteers. Three volunteers were excluded because they felt pain during the introduction of the probe and five because they could not dissociate the contraction of the PFM. The mean of age was 57.96 years (± 6.99; CI: 55.98 - 59.97) in NM and SM was 56.00 years  (± 8.07; CI: 53.80 - 58.20)  (p = 0.79). In NM, the mean time of menopause was 8.38 years (± 6.45, CI: 6.50 - 10.26) and 15.01 years  (± 10.69, CI: 12.09 - 17, 93) in the SM (p = 0.00). The mean age of the menopause was 48.87 years (± 4.57; CI: 48.00 - 49.73) in NM and 40.98 years  (± 7.53; CI: 38.93 - 43.04) at the SM (p = 0.21). Regarding the PFM pressure, NM presented a mean of 34.38 cmH2O (± 23.67; CI: 29.89 - 38.88) and the SM was 27.35 cmH2O (±18.84; CI: 22 , 21-32.49) (p = 0.04).

In the present study, the time of menopause in the SM was higher than the NM. The surgical menopause is indicated by some health problem and frequentely occurs before natural menopause.
A study analyzed the factors that are associated with age and the early menopause, regardless of whether it is natural or surgical, with greater clinical implications. Menopausal time presented almost double between NM and SM, however, there was no statistical difference in PFM manometry between groups (P> 0.05).
Other study evaluated 122 women and analyzed if there is a difference in the strength of the PFM, after muscular training performed in different stages of the menopause. The authors concluded that increased strength and, indirectly, functionality was not influenced by the menopausal period of the participants; however, the menopausal period influenced muscle training, with the early postmenopausal transition phase being less sensitive to strengthening. The hormonal changes can directly affect muscle mass, decreasing by up to 0.6% per year and, consequently, the ability to contract skeletal muscles. 
Perhaps after a certain time of post menopause, the musculature will stabilize as the state of hypoestrogenism. The literature shows that in the postmenopausal period there is a decrease in the amount of estrogenic receptors in the PFM, favoring the atrophy and the weakness of this musculature.

There was no difference in pelvic floor muscle pressure PFM pressure of postmenopausal women with a history of natural and surgical menopause.